I-93 US 4 NB over Sewalls Falls Road
Merrimack County, New Hampshire · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- I-93 US 4 NB over Sewalls Falls Road in Merrimack County, New Hampshire, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 1959, making it 66 years old at the 2025 inventory.
- It carries about 23,491 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 146 of the 326 inventoried bridges in Merrimack County rated good (44.8%); 27 (8.3%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated May 2023, on a 24-month routine inspection cycle.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (43.27381, -71.56105)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Concrete frame |
| Length | about 41 ft |
| Location | 1.4 Mi. S. Jct. Rt 3 Byp. |
| NBI structure number | 005200680012200 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the New Hampshire department of transportation.
Busiest bridges in Merrimack County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-93 Fee Tpk Ramp over Hackett Hill Road | 1978 | 86,013 | Fair |
| I-93 Fee Tpk over Cross Road | 1956 | 82,029 | Fair |
| I-93 Fee Tpk over Ramp A-b | 1957 | 79,640 | Fair |
| I-93 Fee Tpk over Dow Road | 1957 | 78,501 | Fair |
| I-93 Fee Tpk over Robinson Road | 1957 | 78,501 | Fair |
| I-93 Fee Tpk over US 3 Manchester Street | 2000 | 75,054 | Good |
All bridges nearby: Merrimack County, NH bridge conditions · every bridge in Merrimack County · New Hampshire bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.